Conventionally, there are known tower defense games wherein enemy characters move on a route from a starting point to a goal and a player places objects such as weapons on the route to prevent the enemy characters from moving toward the goal, thereby to fulfill the game target (see, e.g., Japanese Patent Application Publication No. 2011-036510 (paragraph 0088)). Also, there are known tower offense games wherein a player moves an ally character from a starting point to a goal while beating enemy characters present on the route, thereby to fulfill the game target.